29 This is to shut up and to cut off the way of grief and of repentance; so that while in all Scripture the Lord God sooths those who return to Him and repent, repentance itself is taken away by our hardness and cruelty, which intercepts the fruits of repentance. But if we find that none ought to be restrained from repenting, and that peace may be granted by His priests to those who entreat and beseech the Lord's mercy, inasmuch as He is merciful and loving, the groaning of those who mourn is to be admitted, and the fruit of repentance is not to be denied to those who grieve.
And because in the place of the departed there is no confession, neither can confession be made there, they who have repented from their whole heart, and have asked for it, ought to be received within the Church, and to be kept in it for the Lord, who will of a surety judge, when He comes to His Church, those whom He shall find within it. But apostates and deserters, or adversaries and enemies, and those who lay waste the Church of Christ, cannot, even if outside the Church they have been slain for His name, according to the apostle, be admitted to the peace of the Church, since they have neither kept the unity of the spirit nor of the Church.
Source: The Epistles of Cyprian (New Advent)